Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D241/00—Heterocyclic compounds containing 1,4-diazine or hydrogenated 1,4-diazine rings
  • C07D241/02—Heterocyclic compounds containing 1,4-diazine or hydrogenated 1,4-diazine rings not condensed with other rings
  • C07D241/06—Heterocyclic compounds containing 1,4-diazine or hydrogenated 1,4-diazine rings not condensed with other rings having one or two double bonds between ring members or between ring members and non-ring members
  • C07D241/08—Heterocyclic compounds containing 1,4-diazine or hydrogenated 1,4-diazine rings not condensed with other rings having one or two double bonds between ring members or between ring members and non-ring members with oxygen atoms directly attached to ring carbon atoms

Definitions

• This invention relates to a process for preparing (S) (+)-4,4'-(1-methyl-1,2-ethanediyl)-bis(2,6-piperazinedione) (hereinafter referred to as "ICRF-187").
• ICRF-187 a process for preparing (S) (+)-4,4'-(1-methyl-1,2-ethanediyl)-bis(2,6-piperazinedione) (hereinafter referred to as "ICRF-187").
• the invention is concerned with a practical process, utilizable on a commercial scale for the preparation of ICRF-187, in which process certain operations hitherto regarded as necessary are avoided, but which process still produces ICRF-187 of the same or better quality in very acceptable commercial yield.
• ICRF-187 was described by Creighton in, inter alia, U.S. Pat. Nos. 3,941,790 and 4,275,063 as a material useful for aiding regression and palliation of cancer in mammals.
• Pathologie Biologie. 1987, 35 (No 1) 49-53 Green described how certain anthracyclines are effective anti-tumour agents but carry the side effect of a tendency to produce cardiotoxicity upon chronic administration, but also disclosed for the first time that ICRF-187 could protect against such cardiotoxicity.
• One particular widely used anti-cancer drug suffering from the disadvantage of associated cardiotoxicity is doxorubicin hydrochloride- In U.S. Pat. No.
• U.S. Pat. No. 4,764,614 describes an alternative synthesis in which propylenediamine tetraacetic acid tetraamide is treated in a dipolar aprotic solvent with an alkali metal derivative of dimethyl sulfoxide to form a dialkali metal salt of the desired bi-piperazinedione, the desired heterocyclic product.
• EP-A-0 330 381 describe yet an alternative process or preparing, inter alia, ICRF-187, in which a corresponding tetranitrile is synthesized by reacting an appropriate diamine with formaldehyde and an alkali metal cyanide. The tetranitrile is then hydrated to yield an acid addition salt of the corresponding tetraamide, and this latter substance may then be cyclized.
• an unprocessable gel often results from precipitating tetraacid product in the presence of alkali metal salt when using an organic solvent/water mix to achieve precipitation.
• This invention is based upon the discovery that, inter lia, separation of most or all alkali metal salt is, most surprisingly, unnecessary prior to cyclization; it is possible efficiently to produce a tetraacid intermediate product which can subsequently be subjected to ring formation by a method known per se thereby to produce ICRF-187 without the hitherto perceived need to remove alkali metal salt and other byproducts at the tetraacid stage.
• the invention enables a process In which a non-isolated tetraacid product is produced which can be dried to prepare a substantially anhydrous mixed powder (which contains byproduct in significant amounts) which can nonetheless be processed, for example, by the method of Creighton, supra, to generate the desired cyclic product, ICRF-187, in a process having as few step as reasonably possible.
• the overall process to ICRF-187 consequently doe not involve the use of dangerous reagents, such as alkali metal cyanides, and additionally avoids expensive and impractical separation stages such as the ion exchange chromatography process of Repta et al, supra.
• the invention is based upon the additional important discovery that deliberate co-precipitation of tetraacid product and alkali metal salt, against the prevailing prejudice, in avoiding salt separation steps used in prior art processes also avoids operations how found to be deleterious.
• organic product extraction is only completely effected after the completion of cyclization.
• the invention provides in one aspect a process for the (S) (+)-4,4 1 -(1-methyl-1,2 ethanediol)-bis-(2,6-piperazinedione) (ICRF-187) in which an intermediate 1,2-diaminopropane tetraacetic acid product is synthesized together with byproduct salt (not necessarily, of course, sodium chloride), characterized in that the tetraacetic acid intermediate product is subjected to ring formation in the form of a crude product having substantial amounts of salt thereby to produce the desired ICRF-187.
• byproduct salt not necessarily, of course, sodium chloride
• the invention provides a process as above in which the tetraacetic acid intermediate product is either the free tetraacid or its disodium salt, the tetraacid intermediate product being isolated by adjusting the reaction mixture pH to about 5.3 to form the disodium salt, or to about 3 or below to form the free acid.
• subsequent processing is substantially unimpeded whatever the pH of the reaction mixture at the stage of formation of the tetraacid, provided this pH is no higher than approximately pH 6.
• a substantially anhydrous product may be produced by adding aqueous reaction mixture containing tetraacid product, eg as obtained by following the method of Repta et al, supra [substantially the method or Wing et al, Inorg.
• the gel which first forms immediately upon precipitation in the solvent/water mixture transforms into crystals within a few minutes. If the pH is, however, lower (and the free acid is the predominant tetraacid product), the gel takes about one hour to transform into crystalline form. These are quite acceptable timings for the production of commercially usable crystalline product for subsequent cyclization.
• a solvent system in which ICRF-187 is soluble but alkali metal salts are not is added to the reaction mix (still containing substantial amounts of formamide).
• Suitable solvents for this purpose are provided by water soluble alcohols, eg n-butanol, but dioxane or tetrahydrofuran (which simply enables the alkali metal salt to be washed away taking advantage of organic/aqueous phase separation) may also be used.
• ICRF-187 resulting from cyclization can be separated from the bulk of salt byproduct by, inter alia, either partition between water and a partially immiscible solvent in which ICRF-187 is soluble but not said salt or fractional crystallization with a solvent system comprising formamide and a lower alcohol.
• initial optical resolution o the starting 1,2-diaminopropane can be conducted via the D-tartaric acid salt as described by Repta et al, supra, and this can be converted into a corresponding hydrochloride salt by treatment with hydrogen chloride in methanol, also as described by Repta et al.
• HCV dihydroxy-3-dihydroxy-3-diaminopropane
• a source of ammonia during the cyclization step of the overall process leads to a clean reaction in which organic product separation from alkali metal salt is more easily effected.
• the nature of the source of ammonia is not critical for this purpose, but a material such as ammonium bicarbonate is preferred because it does not introduce any other "permanent" ionic contamination into the overall reaction mixture (the bicarbonate ion readily decomposing to generate water and carbon dioxide).
• the product may be decolorized with charcoal if desired, and may then be crystallized from dioxane. Preferably at least three dioxane crystallizations are employed to generate a product having a purity higher than 99%. Water crystallization may be employed thereafter.
• the product can De used for therapeutic purposes in accordance with normal practice.
• the invention can thus be expressed in one respect as a process for the preparation of IRCF-187 which consists of reaction between (S)-1,2-diaminopropane and sodium chloroacetate t give (S)-1,2-diaminopropane-N,N,N',N'-tetraacetic acid which is isolated in a crude form as a co-precipitate with reaction by-products (salts) and without further purification subjected to ring formation to obtain ICRF-187.
• the mixture was acidified with concentrated hydrochloric acid (200 ml) and concentrated to 500 ml.
• the resulting solids were filtered off (and found to be without optical activity, ie to not contain product), the filtrate was passed through a column of Dowex 50W-X8 cation-exchange resin (H + form, Bio-Rad Laboratories, Richmond, Calif.) and eluted with boiling water.
• the leavorotatory eluate was concentrated to a small volume, and the crystalline material that formed on standing was separated by filtration and dried.
• the yield of tetraacid was 101 g (49% of theory). Analysis of the mother liquors by optical activity showed them to contain about 5 g of product (2% of theory) (total 51%, c.f. claimed 67%).
• reaction was conducted as in (a) , except that the reaction mixture was acidified with concentrated hydrochloric acid (139 ml) to give pH 5.3, prior to precipitation into methanol (10 1) at 20°.
• the initially-formed gel transformed rapidly into a precipitate which was collected and dried at 70° under vacuum. Yield 234 g (sodium chloride conent: 13%).

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Macromolecular Compounds Obtained By Forming Nitrogen-Containing Linkages In General (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)

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Citations (8)

• 1991
  • 1991-10-25 GB GB919122677A patent/GB9122677D0/en active Pending
• 1992
  • 1992-10-22 AU AU28088/92A patent/AU2808892A/en not_active Abandoned
  • 1992-10-22 WO PCT/GB1992/001942 patent/WO1993008172A1/en active IP Right Grant
  • 1992-10-22 ES ES92921725T patent/ES2138978T3/es not_active Expired - Lifetime
  • 1992-10-22 US US08/211,876 patent/US5618936A/en not_active Expired - Lifetime
  • 1992-10-22 AT AT92921725T patent/ATE182588T1/de active
  • 1992-10-22 DE DE69229677T patent/DE69229677T2/de not_active Expired - Lifetime
  • 1992-10-22 DK DK92921725T patent/DK0611369T3/da active
  • 1992-10-22 EP EP92921725A patent/EP0611369B1/en not_active Expired - Lifetime
  • 1992-10-23 PT PT101006A patent/PT101006B/pt not_active IP Right Cessation
  • 1992-10-23 MX MX9206138A patent/MX9206138A/es unknown
• 1999
  • 1999-10-21 GR GR990402682T patent/GR3031588T3/el unknown

Patent Citations (8)

Non-Patent Citations (8)

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